WASHINGTON (AP) - Political columnist Robert Novak, a diehard conservative, pugilistic debater and proud owner of the "Prince of Darkness" monikor, has died after a battle with brain cancer. His wife of 47 years, Geraldine Novak, told The Associated Press that he died at his home in Washington, D.C. early Tuesday. He was 78. A household face as co-host of . . .